The present invention relates to a new and improved disc brake assembly, and more specifically, to a disc brake assembly including a scraper assembly which engages with the annular braking surface of the disc brake to remove dirt, oil and other contaminants from the braking surface. The disc brake is particularly or adapted for use on a grinding mill.
Mechanisms for cleaning brake surfaces and more particularly disc brake surfaces are known and disclosed in U.S. Pat. No. 3,473,631 entitled Disc Brake And Disc Cleaning Mechanism and U.S. Pat. No. 3,629,814 entitled Disc Brake Rotary Scraper And Wear Indicator Means. In the known disc cleaning mechanisms the scraper assembly is either spring biased into the braking surface or attached to the brake shoe for movement therewith. In both cases, the force between the scraper assembly and the disc varies upon engagement of the scraper assembly with the braking surface.
The present invention provides a new and improved brake assembly which includes a scraper assembly having a scraper blade which is continually biased into engagement with the braking surface. The scraper blade is biased into engagement with the braking surface by a weight which exerts a substantially constant force against the scraper blade to establish a substantially constant force between the scraper blade and the braking surface.
The present invention further provides a new and improved scraper assembly for use with a disc brake including a rotatable disc having an annular braking surface disposed thereon and a caliper assembly including a friction shoe for engaging with the annular braking surface to retard movement of the disc. The scraper assembly includes a scraper blade which continually engages with the annular braking surface on the disc as the disc rotates to remove dirt, oil and other extraneous materials from the braking surface to increase the coefficient of friction of the braking surface, a channel for guiding and supporting the scraper blade in a position in which the scraper blade is engaged with the braking surface and a weight associated with the scraper blade for biasing the scraper blade through the channel into engagement with the braking surface and wherein the force exerted between the scraper blade and the braking surface of the disc is substantially constant.
A still further provision of the present invention is to provide a grinding mill having a cylindrical container rotatable about an axis of rotation for receiving material to be worked therein wherein the cylindrical container includes an annular braking surface thereon disposed substantially perpendicular to the axis of rotation of the mill. A scraper assembly is provided including a scraper blade for continuously engaging the annular braking surface to remove oil, grease and other contaminants from the braking surface. A caliper assembly is provided including a friction shoe which engages with the annular braking surface when the caliper assembly is actuated to retard rotation of the cylindrical container about the axis of rotation. The scraper assembly includes a support for supporting the scraper blade adjacent the annular braking surface in a position in which a first end of the scraper blade is engaged with the braking surface, preventing movement of the scraper blade in a direction tangential to the rotating annular braking surface and providing for movement of the scraper blade in a direction toward and away from the annular braking surface and a weight for biasing the scraper blade through said support into engagement with said annular braking surface.
Another provision of the present invention is to provide a scraper blade for continuously engaging with an annular rotating braking surface of a disc brake for use in a scraper assembly including a channel for guiding movement of the scraper blade toward and away from the annular rotating braking surface and a weight for biasing movement of the scraper blade through the channel. The scraper blade including a first end for continuously engaging with the annular braking surface and a second end for engaging with the weight to enable the weight to bias, with a substantially constant force, the first end of the scraper blade into engagement with the annular braking surface to remove dirt, oil and other contaminants from the braking surface to increase the coefficient of friction of the braking surface.